Valgrind questions

[Thomas Harty <t harty1 physics ox ac uk>]

Dear all,

I've been trying to get clear on exactly what the situation between Gtk+ and Valgrind is. There is a fair 
amount of information out there, but it's pretty scattered and mainly fairly old, so it'd be good to get it 
all in one place.

As far as I understand it, the situation is that memory checkers like Valgrind throw a huge number of errors 
when used on Gtk programmes. This mainly seems to be due to memory which is allocated when the application 
begins, which needs to be kept for the entire lifetime of the programme. Since the memory will be freed by 
the OS when the application closes anyway, Gtk doesn't make an effort to track it and free it at the end.

This creates the problem that even though these aren't harmful, they give us a Valgrind log with thousands of 
entries which is almost impossible to interpret. The way to get around this is to generate a suppression file 
which tells valgrind that we don't want to treat these cases as leaks. We can also tell Gtk not to use some 
of its optimisations which will confuse Valgrind by setting the G_SLICE=always-malloc G_DEBUG=gc-friendly 
flags when we run Valgrind.

So, is this (fairly crude) summary correct and can anyone give me any more info? In particular, generating a 
suppression file from the output of valgrind is non-trivial and a real pain (c.f. 
http://wiki.wxwidgets.org/Valgrind_Suppression_File_Howto).<http://wiki.wxwidgets.org/Valgrind_Suppression_File_Howto%29.>
 It would be better if I knew which places Gtk does things which upset valgrind, so I could write the 
suppression file properly (rather than just trying to reverse engineer it from valgrind's output). So, can 
anyone give me a good explanation of exactly what/where Gtk (does to)/upsets Valgrind? Failing that, does 
anyone have a suppression file that works on the current version of Gtk?

Best wishes,

Tom